Towards the end of a beautiful spring day, students take to the many steps of the slightly stern building that houses the art museum (or Konstmuseet) to catch the lingering rays of the sun.

As the shadows lengthen along the tree-lined Kunsportsavenyn, Gothenburg 's principal boulevard, they move still higher, intent on feeling the last of the day's warmth on winter-white legs.

Below them, an audience shades its eyes against the glare as it makes its way past a fountain with a giant statue of Poseidon and into the city's functionalist concert hall.

Here they will hear Wagner and Richard Strauss (the Alpine Symphony, the one with the wind machine and two tubas) played by the ebullient Gothenburg Symphony Orchestra, directed by Neeme Jarvi, the Estonian maestro who has been its principal conductor for 18 years.

A mile away, the sun is sinking behind the Chiquita banana store, across the water from the five-year-old opera house where a performance of West Side Story (in Swedish) is about to begin. Patrons seem reluctant to leave a terrace from where they watch the light dance on the Gota Canal, where shipbuilding died 20 years ago.

The art museum has closed for the day. But up on the sixth floor, light still floods through a glass roof into galleries of Carl Kylberg, Karl Isakson and the Gothenburg Colourists, whose canvasses vibrate with colours that defy our preconceptions.

Edvard Munch is here too, and some of his pictures are as grim as you would expect: a mother bows by the bed of a sick girl a vampire takes a mouthful from the arm of a woman with long hair. But he is also represented by a portrait of a happy man with a raincoat, yellow hat and green suit beside a brilliant blue sea.

And Strindberg, who dabbled with a brush when he wasn't writing black-mood plays, is here in surprisingly cheerful mood, too, with a nice line of trees tinted orange.

But the picture everyone comes to see is Nordic Summer Evening by Richard Bergh: a couple stand on a verandah overlooking a lake. Like the students on the steps outside, they are enjoying the evening light which catches his watch chain and her belt. Perhaps they are thinking about what they might do when darkness finally comes.

Gothenburg 's light is clear and, thanks to blue trams, gas buses and a surprising absence of traffic, clean. Once the long winter is over, Gotheburgers whip off their thermals and relish every minute of the bright months of the year.

They drink coffee and eat in open-air cafes on Kungsportsavenyn and you would never know that beneath these pavements lurk hot pipes designed to banish the snows of December (and sometimes April). They relax on the benches in Tradgardsforeningens Park and admire the palm house (inspired by Crystal Palace and with 'I Love You' scrawled in the grime of its windows) and the overflowing rose gardens.

They look in the windows of the antique shops in the Haga district, Gothenburg 's oldest suburb, where discreetly-painted wooden houses have been unshowily preserved. A woman crosses the fan cobbles of Haga Nygata with a suitcase on a veteran bath chair. She opens it and arranges the collectables she has for sale: two bottles, an egg-cup, a mincer, a pewter pot.

Nearby, a man sits on an antique bike and talks into a mobile phone. The antiques lady, in floral trousers, produces a folding chair and places it carefully just as the sun begins to falter. The man on the bike rides off past a shop selling bikes even more antique than his own.

Time for a break. Over the canal and past Antikhallarna, a building packed with little shops selling even more antiks. Past Lilla Torget, a small square with a statue of Jonas Alstromer (who introduced the potato to Sweden). Past the city museum, housed in an elegant brick building once the base of the Swedish East India Company, and on to the Kronhuset (Crown House) for tea and cakes in the sun.

The red-brick, steeply-gabled Kronhuset, steeply gabled and built of strong red brick, was built between 1643 and 1655 as Gothenburg 's arsenal and is the city's oldest secular building. It served as the garrison church for 200 years and is now a music school. It is closed to the public, but its bulk guards the peace of a large courtyard where jewellers and glass blowers demonstrate their skills with well-choreographed ease.

From there, it's an easy lope in the early evening sun to the boat museum on the river. The submarine is closed, the scarlet lightship open but deserted. The high-prowed vessel is like the Marie Celeste, with the washing-up still in the galley's sink and the bathroom vacant. The nearby destroyer creaks arthritically with the tide.

But Gothenburg 's best boat experience lies a ferry ride away at a shipyard close to a massive crane now used for bungee jumping. Here, on a slipway last used in 1979, is the only ocean-going ship under construction in Sweden. Not a tanker or a trawler but Gotheborg III, an authentic recreation of an 18th-century East Indiaman which plied between Sweden and China.

The original Gotheborg foundered on a rock just outside the city in 1745, taking to the bottom tea, spices, nine tonnes of fine Chinese blue and white porcelain and the fortunes of many of Sweden's wealthiest mercantile families. In 2004, the 9 million krone Gotheborg III will set sail with 80 crew from the yard's Chinese garden to Canton, 16,304 nautical miles away, according to a signpost pointing vaguely towards the rising sun.

Visitors are welcome and stroll first into an exhibition area which offers no preparation for the shock of seeing the half-made ship when it is at last glimpsed through a glass panel. Its bulk is breathtaking (150ft long, 35ft wide) and so is its smell, a heady mix of glue, pine and oak.

So far, only the bare ribs, like the skeleton of a massive whale, are complete. But stand in what will be the bilges and wonder. You couldn't get this in a flatpack from Ikea. But if you did, one of the 55,000 iron nails made in the yard's own forge would be sure to be missing.

Someone comments that the keel seems very shallow and asks whether that could prove dangerous. It worked well enough before, explains the guide, (although not well enough to stop it sinking). He adds that the vessel will have engines and radar, plus showers, lavatories and real beds.

Across the canal, the design of the new opera house reflects the area's ship building heritage. Outside, there's a hint of prow and crane, oil tanks and the wings of seagulls inside, it's a cruise ship with boat-shaped tables, portholes, companionways, railings and promenade decks. They won't need to build a set if ever they do Billy Budd or The Flying Dutchman.

During the interval of West Side Story (and just before Maria sings Jag ar Vacker), patrons wander about while stuffing half-metre baguettes down their throats with as much dignity as they can muster. Most pause once again to gaze out over the water, relishing every particle of northern light that floods in through a wall of glass.